Over the last few decades, there has been an increase in the occurrence of alien species of mosquitos in Europe. Mosquitos are brought passively into new areas, primarily through the global transport of goods, and if suitable climatic conditions are found there, new populations can establish themselves in these areas. Non-native mosquito species can be "invasive species" if they are shown to lead to changes in the structure and composition of ecosystems and have a detrimental effect on ecosystem services, the human economy and well-being. In the case of alien mosquitoes, there is a particular risk that these species could also spread exotic pathogens.

Reports of alien mosquito species from the public can be essential to quickly detect new populations of these species. Citizen science projects are therefore a valuable addition to monitoring projects carried out by experts. The "Mosquito Alert" app was developed to offer citizens a tool to easily report possible tiger mosquitoes. This app, which is available throughout Europe, was developed as part of the EU project AIM-COST and is coordinated by us in Austria. Users can anonymously upload photos of mosquitoes via the app, which are then scrutinised by several experts. The result is then reported to the user and is also publicly accessible on the project website.

In 2023, 2,955 adult mosquitoes were reported, which was significantly more than in previous years. Most of the reports came from Styria, followed by Vienna, Lower Austria and Upper Austria. 2,311 of the 2,955 reports showed mosquitos (or at least one insect). Of the target species searched for, 568 were Asian tiger mosquitoes and 290 Asian bush mosquitoes. Culex sp. could be identified in 92 reports. Most Asian tiger mosquitoes were reported in Styria, followed by Vienna. Further reports came from Upper Austria, Lower Austria, Tyrol and Carinthia. The findings are very much concentrated in urban areas. Japanese bush mosquitoes were reported from all federal states. Most reports come from Upper Austria, followed by Styria, Lower Austria, Tyrol and Vorarlberg. Sporadic reports came from Salzburg, Carinthia, Vienna and Burgenland.